Effect of Mn on the magnetic and electrical properties of Ho{sub}0.85Tb{sub}0.15Fe{sub}2

摘要

The magnetic properties of C15 type RT{sub}2 (R -^sRare earth, T - 3d Transition metal) cubic Laves phase compounds are of considerable interest due to the localized 4f electrons and itinerant 3d electrons [1]. In these compounds, Fe has an intrinsic magnetic moment, Co has an induced moment due to the rare earth moments and Ni carries zero moment. It has been reported that in the RMn{sub}2 compounds, the magnetic character of Mn atom depends on the Mn-Mn nearest neighbor distances d{sub}(Mn-Mn). An antiferromagnetic ground state has been found for Mn in compounds with d{sub}(Mn-Mn) greater than 2.66A. For the alloys with d{sub}(Mn-Mn) greater than the critical value the Mn moment evolves from a spin fluctuating state at high temperatures to an intrinsic localized moment as the temperature is lowered [2]. Further, the R(Mn,Fe){sub}2 systems are found to exhibit large magnetoresistance because of spin fluctuations and recently a large negative magnetoresistance of 27% has been reported in Ho{sub}0.85Tb{sub}0.15Mn{sub}2 [3,4]. In the present article, we report the effect of Mn substitution for Fe on the temperature dependence of magnetization, AC magnetic susceptibility and electrical resistivity of Ho{sub}0.85Tb{sub}0.15Fe{sub}2.